The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A109734 In A109732, the number 2n+1 appears in position a(n). 5
 1, 2, 5, 3, 30, 6, 28, 4, 38, 26, 11, 7, 36, 29, 14, 8, 201, 39, 34, 27, 180, 12, 175, 9, 199, 37, 46, 31, 25, 15, 178, 10, 242, 202, 49, 40, 197, 35, 54, 32, 192, 158, 23, 13, 208, 176, 57, 16, 240, 200, 61, 41, 83, 47, 195, 33, 121, 42, 67, 17, 190, 179, 70, 18, 689, 243 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS N. J. A. Sloane and Alois P. Heinz, Table of n, a(n) for n = 0..20000 (first 1024 terms from N. J. A. Sloane) EXAMPLE 9 appears in position 30 in A109732, so a(4) = 30. MAPLE with(LinearAlgebra); hit:=Array(1..200000); a:=[1, 3, 7]; hit[1]:=1; hit[3]:=2; hit[7]:=3; S:={15}; L:=7; for n from 4 to 20000 do if (L mod 3 = 0) and hit[L/3]=0 then L:=L/3; a:=[op(a), L]; hit[L]:=n; S:= S minus {L};    if hit[2*L+1]=0 then S:=S union {2*L+1}; fi; else L:=min(S); a:=[op(a), L]; hit[L]:=n; S:=S minus {L};    if hit[2*L+1]=0 then S:=S union {2*L+1}; fi; fi; od: #a; w:=[]; for i from 0 to 50000 do if hit[2*i+1]=0 then break; fi; w:=[op(w), hit[2*i+1]]; od: w; # N. J. A. Sloane, Aug 25 2015 MATHEMATICA (* using the M generated in A109732 *) ms=Sort[M]; k=1; While[ms[[k]]==2k-1, k++ ]; k=k-1; Take[Ordering[M], k] (* T. D. Noe, Aug 10 2005 *) CROSSREFS Cf. A109732. For records see A109739 and A109740. Sequence in context: A246556 A264137 A308949 * A239309 A077073 A307126 Adjacent sequences:  A109731 A109732 A109733 * A109735 A109736 A109737 KEYWORD nonn AUTHOR N. J. A. Sloane, Aug 10 2005 EXTENSIONS More terms from T. D. Noe and Ray Chandler, Aug 10 2005 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 28 15:55 EDT 2020. Contains 334684 sequences. (Running on oeis4.)